Certain types of motor vehicle automatic transmissions utilize what is commonly referred to as a "detent cable" for engaging the passing gear of the transmission. One end portion of the detent cable is connected to the accelerator or to the carburetor linkage and the other end of the cable extends into the transmission housing and is connected to the appropriate mechanism which controls the passing gear. When the motor vehicle accelerator is fully depressed, the detent cable actuates the mechanism for engaging the passing gear. Exemplary of this type of automatic transmission is the transmission commonly employed in nearly all recent General Motors automobiles having a 350 cubic inch engine.
The above-noted type of detent cable, more particularly, includes an elongate interior cable member usually formed of stranded steel wire, with eyelets or other suitable fittings at each end of the cable member for facilitating connection to the appropriate elements of the transmission at one end and to the accelerator or carburetor linkage at the other end. The elongate cable member is encased in a sheath-like cable housing which surrounds the cable member along substantially its entire length. At the end of the cable housing which extends into the transmission, an integrally formed end fitting is provided. The end fitting is conventionally formed of molded plastic and includes a mounting flange for securing the end fitting to the transmission housing and an external circumferential groove located closely adjacent the endmost portion of the end fitting. The circumferential groove is adapted for receiving a sealing member such as an O-ring for forming a seal with the transmission housing to prevent leakage of transmission fluid from the transmission housing when the end fitting is mounted in the transmission housing.
When servicing the automatic transmission, it is normally necessary to disconnect and remove the detent cable from the transmission housing. When removing the end fitting of the detent cable from the transmission housing, the seal-receiving groove is frequently damaged. Apparently, because of the high operating temperatures of the transmission, the integrally molded plastic end fitting becomes brittle and the seal-receiving groove becomes very susceptible to damage.
When the detent cable is damaged in this manner it is normally necessary to replace the entire detent cable, even though the only portion which is damaged is the end fitting which enters the transmission housing and the remainder of the detent cable is otherwise serviceable.
Because the transmission detent cables vary widely in length and other characteristics depending upon the particular automobile model for which they are intended, and because of the expense of the cables, it is impractical for most transmission service establishments to maintain an inventory of all the needed types of replacement detent cables. The replacement detent cables are presently available only from a relatively limited number of sources, and in actual practice it usually becomes necessary for the transmission service mechanic to make a special trip to a repair parts supplier to purchase the necessary replacement detent cable each time a defective detent cable is encountered.
With the foregoing in mind, it is an important object of the present invention to overcome the aforementioned problems and disadvantages arising from the frequent need for replacement of the transmission detent cable when an automatic transmission is serviced.
The present invention provides a method and means for repairing a transmission detent cable wherein only the damaged portion of the cable is replaced so as to thereby facilitate reuse of the otherwise serviceable portions of the original detent cable. More particularly, the present invention provides a unique repair part in the form of a replacement end portion adapted to be secured to the end fitting of the original detent cable after removal of the damaged portion.
The replacement end portion comprises an elongate hollow tubular member having a circumferential external groove at one end thereof of dimensions closely approximating the dimensions of the undamaged seal-receiving groove on the original cable housing end fitting. The opposite end portion of the elongate tubular body includes means forming an axially extending socket of inside dimensions closely approximating the outside dimensions of the integrally formed end fitting. The socket is adapted for receiving therein the end portion of the end fitting which remains after the damaged end portion has been severed and removed. In this manner only the damaged portion of the end fitting is replaced and the otherwise serviceable portions of the detent cable are reused at considerable savings in cost and time.
The method in accordance with this invention comprises severing the end fitting at a predetermined distance inwardly from the damaged seal-receiving groove and removing the damaged portion while leaving the interior cable member and the remaining portion of the end fitting intact. A replacement end portion of the type described above is positioned onto the remaining portion of the end fitting with the axially extending socket of the replacement end portion in coaxial telescoping relation around the remaining end portion of the end fitting. The seal-receiving groove of the replacement end portion is located a predetermined distance beyond the point of severing of the end fitting so as to thereby position the replacement end portion at a location relative to the remainder of the end fitting which is substantially identical to the location of the corresponding portions of the previously removed damaged original end portion. With the replacement end portion so positioned, it is then secured to the remaining portion of the end fitting by suitable means, such as adhesive.